Correlations between behavior, memory, sleep-wake and melatonin in Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS), a neurodevelopmental disorder caused by a microdeletion on chromosomic region 7q11.23, presents with peculiar behavioral and neurocognitive phenotypes that are marked by apparently preserved social and communicative abilities, which contrasts with low overall cognitive and particularly visuospatial performance. In addition, parents often report complaints of sleep disorders and behavioral problems of unknown cause. Sleep is a biological phenomenon that is modulated by the plasma concentration of melatonin and with influence on behavioral aspects and memory. Thus, this study sought to investigate the behavior, memory and the presence of sleep disorders in WBS and to correlate these factors with each other and with the plasma melatonin content. We used the Child Behavior Checklist for ages 6-18 (CBCL), the digit subtest of the Wechsler scale for auditory memory, the visual sequential memory subtest of the Illinois Test of Psycholinguistic Abilities (ITPA) and the Sleep Disturbance Scale for Children (SDSC). Determination of urinary aMT6s, an indirect measure of plasma melatonin content, was held for 72h by ELISA, and the analysis of the circadian rhythm of this content was performed by the Cosinor method. The results of the CBCL showed that 87% of the WBS group presented with a clinical score on the overall competence and total behavioral problems. Furthermore, the behavioral problems that were most frequently reported by parents were anxiety and problems of thought. All individuals with WBS presented with impairments in auditory memory and 47% with impairments in visual sequential memory; 65% of the WBS group presented with an indicative of at least one sleep disorder, where respiratory, initiation and maintenance of sleep (DIMS) and hyperhidrosis were the most frequent disorders. The night time aMT6s levels were lower in individuals with WBS when compared with controls; 53% of the WBS group did not present with circadian rhythm variations in aMT6s levels. In addition, there was a negative correlation between the scores of auditory memory and the total score of sleep disorders and between the DIMS and nocturnal aMT6s content. In conclusion, in the present study, individuals with WBS showed a high frequency of behavioral and memory problems, sleep disturbances and no rhythm variation in aMT6s levels. The low melatonin content may be related with sleep disorders in this population, which, in turn, can have an adverse effect on specific cognitive skills such as memory.

Sono-vigília, aspectos de memória e melatonina em Síndrome de Williams-Beuren: uma revisão de literatura / Sleep-wake, aspects of memory and melatonin in Williams-Beuren syndrome: a review of literature

A Síndrome de Williams-Beuren, distúrbio genético (microdeleção na região cromossômica 7q11.23), apresenta como fenótipo aparente habilidade social que contrasta com o mau funcionamento cognitivo global e visuo-espacial, problemas na forma receptiva, estrutural e semântica da comunicação, além de déficits na atenção, hiperatividade e na memória visuoespacial. Outra caracteristica são desordens no ciclo sono-vigília, com sono ineficaz, resistência em ir para a cama, acordares durante a noite e sonolência durante o dia. Uma possibilidade ainda não explorada nesta síndrome seria o padrão anormal na síntese de melatonina, hormônio capaz de modular a qualidade do sono. Considerando que a qualidade do sono é diretamente influenciada pelos níveis de melatonina e que tanto a melatonina quanto o sono são essenciais para o desenvolvimento adequado das funções cognitivas, buscou-se nesta revisão de literatura quais estudos investigaram separadamente e ou correlacionaram estes três aspectos (melatonina, sono-vigília e memória) na síndrome de Williams-Beuren. Para busca, foram utilizadas as bases de dados Medline/Pubmed, SciELO e Lilacs, com os seguintes descritores: "Williams Beuren syndrome, síndrome de Williams Beuren, memory, memória, sleep-wake, sono-vigília, melatonin e melatonina", por meio de cruzamento e com o conectivo AND. O levantamento bibliográfico mostrou que não existem na literatura trabalhos que correlacionaram estas três variáveis entre si nem tampouco trabalhos que investigaram a melatonina na síndrome de Williams-Beuren. As investigações sobre sono assim como as investigações sobre memória são criticamente discutidas neste trabalho que ressalta a necessidade de estudos que correlacionem estes parâmetros, bem como outros fatores comportamentais, cognitivos e bioquímicos a eles relacionados.

The Williams-Beuren syndrome (WBS), a genetic disorder caused by the hemizygous microdeletion of a region in chromosome 7q11.23 presents an apparent social skill that contrasts with the low global and visuo-spatial cognitive performance, with problems in the receptive, structural and semantic forms of communication, besides deficits in attention, hyperactivity and impairment in visuospatial memory. Another feature is disorders of the sleep-wake cycle with ineffectiveness sleep, resistance to going to bed, waking at night and drowsiness during the day. A possibility not yet explored for this disturbance would be the abnormal pattern in the hormone melatonin that modulate the sleep quality. Considering that the sleep quality is essential for the proper development of cognitive functions, the aim of this literature review was found studies that investigated separately and correlated these three aspects in Williams-Beuren syndrome: sleep-wake, memory and melatonin. In search of data was used Medline/Pubmed, SciELO and Lilacs databases, using the keywords: "Williams Beuren syndrome, memory, sleep-wake and melatonin" separately or using the connective "AND". The literature review showed that there was no studies that correlated these three aspects nor to investigated melatonin in WBS. The investigations on sleep and memory are critically discussed in this work that shows that new studies are necessary to correlate memory, sleep-wake and melatonin in WBS as well as behavioral, cognitive and biochemical aspects related to them.